* validate analyzer properties, do not return `null` for identity analyzer properties
* fix some tests
* Fixed tests for new analyzer parameters validation. Added explicit test for analyzer parameter validation
* update iresearch, fix analyzer tests
* fix more tests
* fix tests
* store analyzer properties as vpack
* more compilation fixes
* Updated iresearch
* Tests compilation fixed
* Test run fixes
* Test run fixes
* Fix test run
* Fixed all IresearchTests
* Fixed V8Analyzers tests
* Added ngram and delimeter analyzers vpack config
* Added ngram and stem analyzers vpack parsers. Added tests
* Fixed internal issue #593 Fixed build issue
* Fixed tests
* Fixed Gtest tests
* Changed test run to fix Mac failure
* Mac tests debugging
* Fixed jslint errors
* test tracing added
* Taken account for VPackSlice operator== false negatives
* Added filtering analyzers before adding them to view link - duplicates are not allowed any more
* Updated test testAddDuplicateAnalyzers - now it tests analyzers with same names but in different databases
* move IResearchViewSort into separate unit
* ensure sort is propagated to IResearchLink
* update iresearch and extend some tests
* implement insertion of sorted values, store value comparator in link
* add tests for VPackComparer
* minor cleanup
* fix issue with sort definiton propagation
* propagate error message from index factory
* add integration tests for sorted indexes, single server
* initial implementation of IResearchViewMergeExecutor
* move iresearch::VPackComparer to separate translation unit
* store collection in IndexReadBuffer for IResearchViewMergeExecutor
* set primary sort from optimizer rule
* add some tests for sorted view case
* extend IResearchViewNode tests
* simplify primary sort definition
* pretty print order condition covered by arangosearch in query explanation
* fix compilation with g++-8
* address catch test failures
* fix tests
* adjust arangosearch optimizer rule to optimize sort in case of cluster
* make tests for sorted indexes work in cluster too
* fix tests
* extend js tests for sorted indices
* fix keyword in query explainer
* ensure sort-limit rule works with views
* backport ngram analyzer fix from upstream
* address jslint errors
* modify IResearchViewSort to support boolean direction specification format
* add some tests
* add tests
* add skip functionality
* extend tests
* add more catch tests
* inline some methods
* address jslint errors
* extend catch tests to reproduce the failure
* add some tests for check fullcount
* add more tests
* extend tests
* temporarily comment out broken tests
* extend js tests
* address review comments
* address jslint errors
* update iresearch
* issue 526.3: update analyzer feature to store analyzer definitions in per-vocbase system collections
* address merge issues
* address another merge issue